The present invention generally relates to a hooked collar, and more particularly to a hooked collar formed on piers for protecting the piers from being scoured.
FIG. 12 illustrates a generally used pier A, water flow B at upstream side is blocked by the pier thereby producing a bow wave B1 on the river surface and a downflow B2 moving downwardly along front side surface of the pier A. The downflow produces a vortex B3 at the river bed C. The vortex B3 scours the river bed. As a result, a scour hole C1 is formed and a caisson foundation A1 of the pier A is uncovered. When the flood scours bottom of the caisson foundation A1, the caisson foundation A1 may cause sink, rupture and evenly collapsing of a bridge.
Therefore, there is a desire to improve such a pier.